This invention relates generally to a bearing mounting arrangement and more particularly to such a mounting with self compensation for thermal expansion.
Screw-type air compressors include meshing rotors, male and female, for the purpose of converting atmospheric air to pressurized air. This process applies axial and radial loads to the rotors. Radial bearings are used for mounting the rotors due to the ability of such bearings to handle these loads. Tight clearances are required to reduce leakage between the meshing rotors, especially at the end of the compressor which discharges the pressurized air.
A supercharger application utilizing the above-described meshing rotors includes gears which synchronize the rotation of the rotors. Tight clearances are also required for these synchronizing gears so that the rotors do not touch. Also, the radial bearings must run true, i.e. no axial or radial floating can be tolerated, under the influence of the axial and radial loads. This floating occurs where there is clearance between the bearing and its mounting boss on the housing or rotor.
In the supercharger application, weight is an important factor and therefore an aluminum housing is used to reduce weight. However, if the steel rotors (or rotor shafts) are placed in an aluminum housing, this introduces a problem of different coefficients of thermal expansion for the steel and aluminum materials. This can cause rotor discharge end clearance problems and the unwanted axial or radial floating, when a temperature change produces clearance around the bearing.
The foregoing illustrates limitations known to exist in present devices. Thus, it is apparent that it would be advantageous to provide an alternative directed to overcoming one or more of the limitations set forth above. Accordingly, a suitable alternative is provided including features more fully disclosed hereinafter.